Carrying the busy A66 between the M6 and Keswick is what is possibly the largest concrete span bridge in Cumbria, the Greta Bridge.
Four lanes of thundering traffic pass over this bridge everyday, however many motorists are unaware of the valley below or what an achievement it was to build it.
The structure, is said to have been designed purely by engineers with no architectural input and is renowned for its aesthetic qualities which ensure it blends well with the surrounding Lake District countryside.
Opened in 1977 Greta Bridge spans the River Greta and is sandwiched between the edge of the town of Keswick and the fells including Latrigg.
Passing underneath the bridge is the National Cycle network route 71.
This path and the associated Keswick railway footpath uses the old track bed of the Keswick railway which closed in 1972.
Construction began on the bridge in 1974 and forms part of the Keswick Northern Bypass project.
With five spans the 220m long structure sits on very tall pillars spanning the valley below.
It was one of the longest bridges of it’s type at the time.
The bridge is said to be one of the first structures to be designed using finite element analysis.
One of the major structural engineers involved in the bridge design and in particular the use of pre-stressed concrete in road building was Roy Rowe.
He devised mathematical formulae to work out stresses and loads on concrete structures and was to become one of the leading experts in the use of concrete as a building material in civil engineering.
Roy Rowe died of heart disease on December 18, 2008, aged 79.
Writing in the NCE (New Civil Engineer) Mr. Peter Donaldson who was the structures Agent for the main contractor Tarmac Construction, says that the building of Greta Bridge was not without difficulty.
Mr Donaldson writes “In plan, the bridge follows a reverse curve which requires a constantly changing carriageway crossfall from one abutment to the other. In turn, this varying crossfall geometry is repeated in the cross sectional alignment of the deck itself, resulting in webs which, although apparently vertical, are actually at right angles to the deck soffit and upper slab”.
Mr Donalson was writing to the letters section of the New Civil Engineer in response to the announcement that the Great Bridge had been nominated as Britain’s best civil engineering structure of the century (NCE 4 November 1999).
Mr Donaldson adds ” I think I can speak for all of us involved in its construction when I say that we remain immensely proud of what we achieved”
In 1977 the bridge was awarded a Highly Commendation by the Concrete Society.
Readers of Concrete magazine however voted it Best Civil Engineering Structure of the Century in 1999.
Beverley Hughes MP, Minister for the Environment, unveiled a plaque, which is positioned beneath the bridge.
The Plaque reads:- ‘GRETA BRIDGE Voted Best Concrete Engineering Structure Of The Century September 1999 / Consulting Engineer : Scott Wilson Kirkpatrick & Partners / Contractor : Tarmac Construction / Maintained by The Highways Agency.
The urban morphology of Keswick
Location details from Google Maps 54.605880, -3.114635 +54° 36′ 21.17″, -3° 6′ 52.69″ Link: